In general, this disclosure includes systems, methods, and techniques for inducing electrical current through one or more battery banks. For example, a circuit may include a switching element. The circuit may be configured to draw, using the switching element, a current from a first battery bank when the switching element is turned on, the first battery bank emitting an excess current after the switching element is turned off, where the current increases a temperature of the first battery bank. Additionally, the circuit may be configured to deliver at least some of the excess current to a second battery bank when the switching element is turned off, where the excess current charges the second battery bank, and where the excess current increases a temperature of the second battery bank.